Reacting a (meth)acrylic anhydride with a diamine to form a n-dialkylaminoalkyl(meth)acrylamide

Abstract

The present invention relates to a process for the preparation of an N-dialkylaminoalkyl(meth)acrylamide of formula: ##STR1## in which: R 1 is a methyl radical or a hydrogen atom, R 2 is a straight-chain or branched alkyl group containing at most 10 carbon atoms R 3 and R 4 , which are identical or different, may be: either two aliphatic alkyl groups containing from 1 to 4 carbon atoms, or R 3 is an aliphatic alkyl group containing from 1 to 4 carbon atoms and R 4 is an alicyclic group containing from 5 to 6 carbon atoms, or R 3 and R 4 are two alicyclic groups containing from 5 to 6 carbon atoms, or R 3 and R 4 form, together with the nitrogen atom to which they are chemically linked, a heterocycloaliphatic group. This process is characterized in that a (meth)acrylic anhydride of formula: ##STR2## is reacted with a diamine of formula: ##STR3## in the presence of a polymerization inhibitor.

We claim: 
     
       1. A process for the synthesis of a N-dialkylaminoalkyl(meth)acrylamide of the formula: ##STR9## in which: R 1  is methyl or hydrogen, R 2  is alkyl group containing at most 10 carbon atoms,   R 3  and R 4 , being identical or different, each represent an: aliphatic alkyl group containing from 1 to 4 carbon atoms, or an alicyclic group containing from 5 to 6 carbon atoms; or R 3  or R 4 , together with the nitrogen atom to which they are chemically linked, represent piperidino or pyrrolidino, which process comprises reacting a (meth)acrylic anhydride of the formula: ##STR10## with a diamine of the formula: ##STR11## in the presence of at least one polymerization inhibitor at a temperature of between 70° and 100° C. and in the presence of oxygen, and separating resultant N-dialkylaminoalkyl(meth)acrylamide.     
     
     
       2. A process according to claim 1 wherein the N-dialkylaminoalkyl(meth)acrylamide obtained is separated by distillation and in that, before the reaction between (meth)acrylic anhydride and the diamine, after said reaction, or both before and after said reaction, there is added to the reaction mixture an organic solvent which is inert to the reaction mixture, which forms a homogeneous mixture with the latter, and which has a boiling temperature lying between that of (meth)acrylic acid and that of the N-dialkylaminoalkyl(meth)acrylamide. 
     
     
       3. Process according to claim 2, characterized in that the quantity of solvent which is introduced into the reaction mixture is between 10 and 50% by weight based on the total charge of the reactants. 
     
     
       4. Process according to claim 3, characterized in that the quantity introduced into the reaction mixture is between 20 and 30% by weight based on the total charge of the reactants. 
     
     
       5. A process according to claim 1, wherein the inert solvet is 1,2,4-trichlorobenzene. 
     
     
       6. A process according to claim 1, wherein the N-dialkylaminoalkyl(meth)acrylamide obtained is separated by extraction with an organic solvent after neutralization of the reaction mixture using a strong base. 
     
     
       7. A process according to claim 1, wherein the molar ratio of (meth)acrylic anhydride to the diamine is between 1 and 1.2. 
     
     
       8. A process according to claim 1, wherein the quantity of polymerization inhibitor is such that the weight ratio of this inhibitor to the (meth)acrylic anhydride is at least 0.25%.